Democrat Sen. Mary Landrieu of Louisana asked for the vote on the Keystone XL pipeline to help her retain her Senate seat. She got the vote but fell short of the filibuster-proof threshold of 60 votes.

After six years of debate and delay, the Senate rejected a bill to authorize the Keystone XL pipeline.

Democrats blocked final passage even though one of their own pushed for the vote. The pipeline is popular in Louisiana where Landrieu faces a December run-off election to keep her seat.

"This is for Americans. For American jobs to build an American middle class,” Landrieu said.

Many of her colleagues called the pipeline a threat to the environment.